TM 9-2350-247-10DESCRIPTION AND USE OF DRIVERS CONTROLS AND INSTRUMENTS  Continued 0004 000004 00-14Light comes on when parking brake is set.PARKING BRAKEINDICATOR LIGHTTurns ON and OFF all exterior driving and instrument panel lights.DRIVING LIGHTS SWITCHTable 14. DRIVERS INSTRUMENT PANEL - M548A3 (Continued)Light comes on when headlight high beams are on.HEADLIGHTS HIGH BEAMINDICATOR LIGHTKEYPress switch to sound carrier horn.HORN SWITCHCONTROL OR INDICATORLight comes on when oil pressure is too low for safe operation. Lightshould off 10 seconds after engine starts.FUNCTIONENGINE OIL LOW PRESSWARNING LIGHTLight comes on when transmission oil temperature is too high for safeoperation.TRANS OIL HIGH TEMPWARNING LIGHT